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Grumman G-70 / AF-2 Guardian


AF-2W (nearest) and AF-2S (rear)

In 1944 Grumman set out to produce a successor to the war-winning TBF Avenger torpedo bomber with a composite power plant consisting of an R-2800-34W piston engine in the nose and a Westinghouse 19XB-2B turbojet engine in the rear fuselage, and the first result was the XTBF-1 (G-70), first flown on 19 December 1945. Looking like a slimmer and neater TBF, this machine had a Westinghouse J30 (later an Allis-Chalmers J36, otherwise de Havilland Goblin) turbojet in the tail for high-speed boost propulsion. This was later omitted.

In 1949 two new prototypes incorporating all the changes were built (carrying the designations XTB3F-1S and XTB3F-2S) the former equipped as a submarine hunter and the latter as a killer.

Both types were ordered by the US Navy under the respective designations AF-1S and AF-2S, but before completion of the first AF-1S its designation was changed to AF-2W.

It was put into production in two versions, which operated from US Navy carriers in the ASW (anti-submarine warfare) role in pairs, known as hunter/killers.

The hunter was the AF-2W, distinguished by its APS-20A search radar, the displays and controls for which were in a two-seat rear compartment. The AF-2W carried a large search and early-warning radome beneath the forward fuselage.

The killer was the AF-2S, which took over when its companion had obtained a sure ‘contact’. First it used its smaller APS-30 radar under the right outer wing to pinpoint its target, using a searchlight in an identical pod under the left wing to illuminate it if necessary. Then it would attack using any of its assortment of weapons.

The AF-2S Guardian (G-82) carried one 900kg torpedo, two 720kg depth charges or two 900kg bombs internally, while a similar load could be carried externally. In addition a searchlight was carried under the port wing and a radar scanner under the starboard.



In 1952-53 the AF-3S version was produced with additional submarine detection gear.

The Guardians were among the largest single-engine military aircraft, heavier than a Douglas DC-3 and with a roomy side-by-side cockpit, the AF-2S having a third rear-compartment seat for the single radar operator. Grumman delivered 193 of the AF-2S attack version and 153 of its companion AF-2W model in 1950-3. The company then followed with 40 AF-3S machines, which were the first aircraft in service with MAD (magnetic-anomaly detection) gear in a retractable tail-boom mounting.

Production of the Guardian ended in March 1953.

AF-2S Guardian
Powerplant: one 2,400-hp (1790-kW) Pratt & Whitney R-2800-48W 18-cylinder radial piston engine.
Maximum speed: 510 km/h (317 mph) at medium/high altitude
Service ceiling 9910 m (32,500 ft)
Range 2415 km (1,500 miles)
Empty weight 6632 kg (14,620 lb)
Maximum take-off 11567 kg (25,500 lb)
Wing span 18.49 m (60 ft 8 in)
Length 13.21 m (43 ft 4 in)
Height 4.93 m (16 ft 2 in)
Wing area: 52.02 sq.m (560.0 sq ft)
Armament: internal bay for 1814 kg (4,000 lb)
Crew: 3







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